The present invention is related to an apparatus and method for reducing a hazardous gas content of an effluent from a process chamber.
Fluorocarbon, chlorofluorocarbons, hydrocarbon, and other fluorine containing gases are widely used in the manufacture of integrated circuits in process chambers. These gases are chemically toxic to humans and hazardous to the environment. In addition, they may also strongly absorb infrared radiation and have high global warming potentials. Especially notorious are persistent fluorinated compounds or perfluorocompounds (PFCs) which are long-lived, chemically stable compounds that have lifetimes exceeding thousands of years. Some examples of PFCs are carbon tetrafluoride (CF4), hexafluoroethane (C2F6), perafluoropropane (C3F8), trifluoromethane (CHF3), sulfur hexafluoride (SF6), nitrogen trifluoride (NF3), carbonyl fluoride (COF2) and the like. For example, CF4 has a lifetime in the environment of about 50,000 years and can contribute to global warming for up to 6.5 million years. Thus it is desirable to have an apparatus or method that can reduce the hazardous gas content of effluents, and especially PFC""s, that may be released from the process chambers.
Perfluorocompounds are utilized in numerous semiconductor fabrication processes. For example, perfluorocompounds are used in the etching of layers on substrates, such as oxide, metal and dielectric layers. Perfluorocompounds can also be used during chemical vapor deposition processes. Additionally, process chambers can be cleaned of etch or deposition residue using perfluorocompounds. These hazardous compounds are either introduced into a process chamber or are formed as byproducts within the process chamber and may be exhausted from the chamber in an effluent gas stream.
It is necessary for the health of our environment to minimize the introduction of harmful gases and byproducts into atmosphere. There is also a need to minimize the harmful content of the effluent gas in an efficient and inexpensive manner. There is a further need to reduce PFC and other harmful gases to the lowest possible levels especially for industries which widely use PFCs, even though such use is a relatively small component of the overall consumption or release of PFCs in the world.
The present invention reduces a content of hazardous gases, such as PFCs, in a simple and efficient manner. The present invention is useful for reducing the hazardous gas content of effluent gas resulting from processing of substrates, such as semiconductor wafers and other electronic devices. By hazardous gas it is meant any toxic, harmful or undesirable gas, such as, but not limited to PFCs, CFCs, hydrocarbons, other fluorine containing gases, and other undesirable gases.
In one aspect of the invention, a gas treatment apparatus for reducing a hazardous gas content of an effluent from a chamber comprises a reactor adapted to receive the effluent, the reactor including a consumable material capable of reacting with the effluent to remove hazardous gas therefrom, and a gas energizer adapted to energize the effluent in the reactor.
In another aspect of the invention, a gas treatment apparatus for reducing a hazardous gas content of an effluent from a chamber comprises a reactor adapted to receive the effluent, the reactor including a dielectric interior surface capable of reacting with the effluent to remove hazardous gas therefrom and a gas energizer adapted to energize the effluent in the reactor.
In another aspect of the invention, a method of treating an effluent from a chamber to reduce the hazardous gas content therein comprises introducing effluent gas into a reactor, introducing an oxygen containing gas into the reactor, and energizing the effluent and oxygen containing gases in the reactor to reduce the hazardous gas content therein.
In another aspect of the invention, a gas treatment apparatus for reducing hazardous gas content of an effluent from a chamber comprises a gas reactor adapted to receive the effluent and a gas energizer adapted to energize the effluent in the reactor, and a catalytic reactor adapted to catalyze reactions in the effluent to reduce the hazardous gas content thereof.
In another aspect of the invention, a method of treating an effluent to reduce the hazardous gas content thereof comprises introducing effluent gas into a gas reactor and energizing the effluent gas in the gas reactor, and introducing the effluent gas into a catalytic reactor to catalyze reactions in the effluent gas whereby the hazardous gas content of the effluent gas is reduced. The steps may occur in any order.
In another aspect of the invention, a method of reducing recombination of radicals into hazardous gases comprises inductively heating hazardous gas to form inductively heated radicals and introducing the inductively heated radicals into a catalytic reactor to catalyze favorable reactions and thereby reduce hazardous gas recombination.
In another aspect of the invention, a method of treating an effluent from a process chamber to reduce the hazardous gas content thereof comprises introducing effluent gas from a process chamber into a catalytic reactor at a temperature below about 400xc2x0 C., and passing the effluent gas through the catalytic reactor to catalyze reactions in the effluent and thereby reduce the hazardous gas content thereof.